This invention relates to optical monitoring systems.
Optical sensors provide a convenient method of monitoring a range of physical properties of a location. The relative simplicity and robustness of optical sensors and the ability to locate the sensor significant distances from more complex interrogation hardware make optical systems particularly attractive where the sensor is to be located in hostile environments.
A particular family of optical sensing systems utilises a light source and detector (interrogator) located at a convenient interrogator location some distance from the actual sensors, with a fibre optic connection between. A particular application of such sensing systems is the marine oil and gas industry for seismic sensing, where the sensors are located on the sea floor and the interrogation location is on a surface platform or vessel.
Connecting the sensors to the interrogator requires a reliable optical connection extending over considerable distances. Particularly in the marine environment that connection is provided by specialist optical cables which are cumbersome and costly. A principle factor in the cost of the connection cable is the number of optical fibres and connectors utilised.
There is therefore a requirement to reduce the number of optical fibres utilised to connect an interrogator system to sensor arrays.